diff --git a/src/lib.rs b/src/lib.rs
index a5ecdad..ac69537 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,7 @@
 #![no_main]
 #![no_std]
 
+use core::sync::atomic::{AtomicUsize, Ordering};
 use defmt_brtt as _; // global logger
 
 // TODO adjust HAL import